[web] seperate out each reaction into their own pill

Summary:
The next step to redesigning the InlineEngagement component is to split out each reaction into its own pill.

Depends on D8707

Test Plan:
Please see the demo video below

Reviewers: atul, kamil

Reviewed By: atul

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D8708